The nature of family relationships is a critical measure for healthcare professionals who work with families. In particular, non-Western cultural groups display a higher level of collectivism that emphasizes relationships between family members. This paper reports the development and psychometric testing of a new scale, the Korean Family Relationship Assessment Scale (FRAS). Using DeVellis' Guidelines in Scale Development, a pool of 40 items was created after a review of the literature, followed by an assessment for content validity by six experts. Both exploratory and confirmatory factor analyses were conducted with data from a sample of 217 Korean family triads (father, mother, and college-aged offspring) (N = 651). The final evaluation yielded three factors with 15 items: family support, family conflict, and family togetherness. Since the FRAS demonstrated good internal consistency and validity, it would be able to facilitate research on the relationships between family support, conflict, togetherness, and health. Applying this new instrument in theory-based research may contribute to knowledge about the role of the family in the health and well-being of family members within a Korean context. For clinical practice, this culturally sensitive and valid instrument has the potential to measure changes in family relationships after family therapy or interventions.